Because of inherent variations of color across a coated surface, which may be due to, for example, poor coating applications, unstable paint chemistries, natural fluctuations of special pigments such as micas and xirallics, statistical measurement control (“SMC”) is often employed to remove errant or inaccurate data that result from such variations. Also, SMC is often used to ameliorate the effects of measuring an erroneous area or an area that is not representative of the rest of the coated surface that is being measured. Such areas of concern include, for example, scratches in the surface, dust, fingerprints, coating defects, or areas in which the spectrophotometer aperture is not kept fully on the coating.
Typically, SMC has been completed using colorimetric data (e.g., as L*, a*, and b*) on an angular basis using confidence intervals with rigid requirements. However, such methods are not always accurate in removing errant or inaccurate data obtained from spectrophotometric measurements. Thus, there is a need for systems and methods that use spectral reflectance data, instead of colorimetric derivations, and that allow for flexible tolerances.